1. Technical Field
The present invention relates to a stabilizer for a motor boat, and more particularly, to a motor mounted stabilizer for stablely maintaining the hull of the boat essentially parallel to the surface of the water.
2. Related Art
Motor boats experience performance problems due to the usual location of the motor at the rear (stern) of the boat, causing drag and and resulting in the front (bow) of the boat lifting out of the water. At high speeds, the lifting of the bow becomes more pronounced, blocking the view of the boat operator, and preventing safe steering of the boat. In an attempt to overcome this problem, many boat operators place passengers or other weight in the forward part of the boat so as to hold the bow down. However, the excess weight results in sluggish boat operation and reduced engine efficiency. Additionally, since a substantial part of the hull is out of the water, the boat tends to skip or slide during high speed turns.
A second performance problem occurring at high speed operation is known as "porpoising", that is, the tendency of the bow of the boat to oscillate between an extreme lifted position and a contact position with the water. This oscillation occurs rapidly, causing the bow to slam against the water surface, and then return to an extreme lifted position. "Porpoising" increases the difficulty of controlling the boat, as well as the roughness of the ride and passenger discomfort. Skipping or sliding during turns is also increased during "porpoising".
A third performance problem is experienced during acceleration from a stop. During acceleration, it is desirable to achieve "planing" mode, that is, when the flat surface of the hull is essentially in full contact with the water, as soon as possible. However, due to the above discussed tendency of the stern of the boat to sink beneath the surface of the water, causing the bow to be lifted out of the water during high-speed operation, planing of the boat during rapid acceleration is difficult or impossible to achieve. Thus, in order to obtain satisfactory acceleration, increased fuel consumption is required since the motor must operate at higher RPM to obtain high speed when a substantial part of the hull is out of the water.
One attempt to overcome the above problems is disclosed in Larson U.S. Pat. No. 4,487,152, which is directed to a boat stabilizer fitted over the cavitation plate on the motor post of the motor. The stabilizer is a generally delta wing shaped foil member and is attached at a position over the propeller to provide upward lift for the stern, apparently in the same manner as an airplane wing provides lift for the airplane as air rushes over it. However, in practice only limited success has been obtained with the wing stabilizer in eliminating the undesirable effect of "porpoising" at medium or high boat speeds. Furthermore, the wing-shaped stabilizer provides only minimal improvement in reducing skipping or sliding during turns.